infrasonic rumble can destroy you woofers. especially when listenning at high volumes! My NAD phono preamp does not need a rumble filter as it always cuts those ultrasonic noises. With my former phono preamp (ATOLL) woofers were moving excessivly producing infrasonic bass.
Why don't all phono preamps include a rumble filter?
In my system, the use of a rumble filter is mandatory (I notice no degradation of sonics when I engage the rumble filter). I'm thinking of upgrading my phono preamp and would like to choose one that has this as an optional feature. However, it appears that most manufacturers of phono preamps do not include this. Why not? Does the use of a rumble filter degrade the sound of a phono preamp?